The housing of a measurement instrument typically is comprised of top and bottom halves that are assembled together to form an enclosure for electronic circuitry. To seal the instrument from dust and water, and to provide a non-slip surface to the housing so that the instrument can be propped up, a gasket, ordinarily made of an elastomeric material, is located between the halves.
For example, with reference to FIG. 1, in instrument housing of the prior art has top and bottom portions 20 and 22 enclosing a circuit board 24 containing electronic components and circuit wiring. Between the housing portions 20, 22 there is a gasket 26 that is provided as a separate piece in the form of an elastomeric strip, banded around the outer surface of the lower portion 20 of the instrument housing. The corners of the housing may be rounded as shown. When the top and bottom portions 20, 22 of the housing are assembled, the gasket 26 becomes sandwiched between them to form the seal.
While generally satisfactory, this type of seal has certain deficiencies. For example, the instrument housing must be able to withstand impacts, such as would be caused by dropping, without dislodging the seal. However, portions of the prior art gasket outside the rounded corners of the housing tends to dislodge from the region between the top and bottom portions when the instrument housing is dropped. This also occasionally occurs when the instrument is inserted in or removed from a holster.
Once dislodged from the housing, the gasket is not easy for the user to reinstall. Furthermore, original assembly of the housing is difficult because the gasket, to be reasonably secure so that it does not dislodge, must be adhered to one of the housing halves using an adhesive, and this requires an additional manufacturing step.